In particular, we monitored the protein expression levels in the cell lines that represent models for HER2+ (SKBR3 and MDA-MB-453), Triple Negative Breast Cancer (TNBC) (MDA-MB-231 and MDA-MB-361), Luminal A (MCF-7 and T47D), and Luminal B (BT474) breast cancer subtypes [30,31]. This evidence concerns the gene ERBB2 and breast cancer.